In a certain experiment, 20.0 mL of bromine (density 5 3.10 g/mL) was reacted with excess aluminum to yield 50.3 g of aluminum bromide. What is the percent yield for this experiment?

Two cars collide, lock bumpers and move together after the collision.this collision is known as perfectly inelastic collision.

I'm having some difficulty seeing the diagram clearly.but the question says there's a net inward force on the object.so we know right away,  from newton's 2nd law of motion, thatthat baby is accelerating.  it doesn't even matter which way thenet force is pointing.  if there's any net force, then either theobject's speed or else its direction must be changing.